package xin.xihc.jba.core.bean;

import com.fasterxml.jackson.core.type.TypeReference;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.*;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.dao.DataRetrievalFailureException;
import org.springframework.dao.InvalidDataAccessApiUsageException;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import xin.xihc.jba.annotation.Alias;
import xin.xihc.jba.annotation.Column;
import xin.xihc.jba.annotation.JsonHandler;
import xin.xihc.jba.core.utils.FieldCache;
import xin.xihc.utils.common.CommonUtil;
import xin.xihc.utils.json.JsonUtil;

import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.lang.reflect.ParameterizedType;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.*;
import java.util.stream.Collectors;

/**
 * 自定义行映射关系
 *
 * @author Leo.Xi
 * @version 1.0
 * @date 2019/4/30 17:40
 **/
public class JbaBeanPropertyRowMapper<T> implements RowMapper<T> {

    protected static final LinkedHashMap<Class<?>, JbaBeanPropertyRowMapper<?>> RowMapper_CACHE = new LinkedHashMap<>();

    /**
     * Logger available to subclasses
     */
    protected final Log logger = LogFactory.getLog(getClass());

    /**
     * The class we are mapping to
     */
    private Class<T> mappedClass;

    /**
     * Whether we're strictly validating
     */
    private boolean checkFullyPopulated = false;

    /**
     * Whether we're defaulting primitives when mapping a null value
     */
    private boolean primitivesDefaultedForNullValue = false;

    /**
     * ConversionService for binding JDBC values to bean properties
     */
    private ConversionService conversionService = DefaultConversionService.getSharedInstance();

    /**
     * Map of the fields we provide mapping for
     */
    private Map<String, PropertyDescriptor> mappedFields;

    /**
     * Set of bean properties we provide mapping for
     */
    private Set<String> mappedProperties;

    /**
     * Create a new {@code BeanPropertyRowMapper}, accepting unpopulated
     * properties in the target bean.
     * <p>Consider using the {@link #newInstance} factory method instead,
     * which allows for specifying the mapped type once only.
     *
     * @param mappedClass the class that each row should be mapped to
     */
    public JbaBeanPropertyRowMapper(Class<T> mappedClass) {
        initialize(mappedClass);
    }

    /**
     * Create a new {@code BeanPropertyRowMapper}.
     *
     * @param mappedClass         the class that each row should be mapped to
     * @param checkFullyPopulated whether we're strictly validating that
     *                            all bean properties have been mapped from corresponding database fields
     */
    public JbaBeanPropertyRowMapper(Class<T> mappedClass, boolean checkFullyPopulated) {
        initialize(mappedClass);
        this.checkFullyPopulated = checkFullyPopulated;
    }

    /**
     * Static factory method to create a new {@code BeanPropertyRowMapper}
     * (with the mapped class specified only once).
     *
     * @param mappedClass the class that each row should be mapped to
     */
    public static <T> org.springframework.jdbc.core.BeanPropertyRowMapper<T> newInstance(Class<T> mappedClass) {
        return new org.springframework.jdbc.core.BeanPropertyRowMapper<T>(mappedClass);
    }

    /**
     * Get the class that we are mapping to.
     */
    public final Class<T> getMappedClass() {
        return this.mappedClass;
    }

    /**
     * Set the class that each row should be mapped to.
     */
    public void setMappedClass(Class<T> mappedClass) {
        if (this.mappedClass == null) {
            initialize(mappedClass);
        } else {
            if (this.mappedClass != mappedClass) {
                throw new InvalidDataAccessApiUsageException(
                        "The mapped class can not be reassigned to map to " + mappedClass + " since it is already providing mapping for " + this.mappedClass);
            }
        }
    }

    /**
     * Return whether we're strictly validating that all bean properties have been
     * mapped from corresponding database fields.
     */
    public boolean isCheckFullyPopulated() {
        return this.checkFullyPopulated;
    }

    /**
     * Set whether we're strictly validating that all bean properties have been mapped
     * from corresponding database fields.
     * <p>Default is {@code false}, accepting unpopulated properties in the target bean.
     */
    public void setCheckFullyPopulated(boolean checkFullyPopulated) {
        this.checkFullyPopulated = checkFullyPopulated;
    }

    /**
     * Return whether we're defaulting Java primitives in the case of mapping a null value
     * from corresponding database fields.
     */
    public boolean isPrimitivesDefaultedForNullValue() {
        return this.primitivesDefaultedForNullValue;
    }

    /**
     * Set whether we're defaulting Java primitives in the case of mapping a null value
     * from corresponding database fields.
     * <p>Default is {@code false}, throwing an exception when nulls are mapped to Java primitives.
     */
    public void setPrimitivesDefaultedForNullValue(boolean primitivesDefaultedForNullValue) {
        this.primitivesDefaultedForNullValue = primitivesDefaultedForNullValue;
    }

    /**
     * Return a {@link ConversionService} for binding JDBC values to bean properties,
     * or {@code null} if none.
     *
     * @since 4.3
     */
    public ConversionService getConversionService() {
        return this.conversionService;
    }

    /**
     * Set a {@link ConversionService} for binding JDBC values to bean properties,
     * or {@code null} for none.
     * <p>Default is a {@link DefaultConversionService}, as of Spring 4.3. This
     * provides support for {@code java.time} conversion and other special types.
     *
     * @see #initBeanWrapper(BeanWrapper)
     * @since 4.3
     */
    public void setConversionService(ConversionService conversionService) {
        this.conversionService = conversionService;
    }

    /**
     * Initialize the mapping meta-data for the given class.
     *
     * @param mappedClass the mapped class
     */
    protected void initialize(Class<T> mappedClass) {
        this.mappedClass = mappedClass;
        if (!RowMapper_CACHE.containsKey(mappedClass)) {
            this.mappedFields = new LinkedHashMap<>(16);
            this.mappedProperties = new HashSet<>();
            // 所有属性
            List<Field> allFields = FieldCache.getAllFields(mappedClass);
            PropertyDescriptor[] pds = BeanUtils.getPropertyDescriptors(mappedClass);
            for (PropertyDescriptor pd : pds) {
                if (pd.getWriteMethod() != null) {
                    this.mappedFields.put(lowerCaseName(pd.getName()), pd);
                    String underscoredName = underscoreName(pd.getName());
                    if (!lowerCaseName(pd.getName()).equals(underscoredName)) {
                        this.mappedFields.put(underscoredName, pd);
                    }
                    // 增加字段映射关系
                    Optional<Field> field = allFields.stream().filter(x -> pd.getName().equals(x.getName()))
                            .findFirst();
                    field.ifPresent(f -> {
                        // @Column
                        Column fColumn = f.getAnnotation(Column.class);
                        if (null != fColumn && CommonUtil.isNotNullEmpty(fColumn.value())) {
                            this.mappedFields.put(fColumn.value(), pd);
                        }
                        // @Alias
                        Alias fAlias = f.getAnnotation(Alias.class);
                        if (null != fAlias) {
                            for (String as : fAlias.value()) {
                                this.mappedFields.put(as, pd);
                            }
                        }
                    });
                    this.mappedProperties.add(pd.getName());
                }
            }
            RowMapper_CACHE.put(mappedClass, this);
        } else {
            this.mappedFields = RowMapper_CACHE.get(mappedClass).mappedFields;
            this.mappedProperties = RowMapper_CACHE.get(mappedClass).mappedProperties;
        }
    }

    /**
     * Convert a name in camelCase to an underscored name in lower case.
     * Any upper case letters are converted to lower case with a preceding underscore.
     *
     * @param name the original name
     * @return the converted name
     * @see #lowerCaseName
     * @since 4.2
     */
    protected String underscoreName(String name) {
        if (!StringUtils.hasLength(name)) {
            return "";
        }
        StringBuilder result = new StringBuilder();
        result.append(lowerCaseName(name.substring(0, 1)));
        for (int i = 1; i < name.length(); i++) {
            String s = name.substring(i, i + 1);
            String slc = lowerCaseName(s);
            if (!s.equals(slc)) {
                result.append("_").append(slc);
            } else {
                result.append(s);
            }
        }
        return result.toString();
    }

    /**
     * Convert the given name to lower case.
     * By default, conversions will happen within the US locale.
     *
     * @param name the original name
     * @return the converted name
     * @since 4.2
     */
    protected String lowerCaseName(String name) {
        return name.toLowerCase(Locale.US);
    }

    /**
     * Extract the values for all columns in the current row.
     * <p>Utilizes public setters and result set meta-data.
     *
     * @see java.sql.ResultSetMetaData
     */
    @Override
    public T mapRow(ResultSet rs, int rowNumber) throws SQLException {
        Assert.state(this.mappedClass != null, "Mapped class was not specified");
        T mappedObject = BeanUtils.instantiateClass(this.mappedClass);
        BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(mappedObject);
        initBeanWrapper(bw);

        ResultSetMetaData rsmd = rs.getMetaData();
        int columnCount = rsmd.getColumnCount();
        Set<String> populatedProperties = (isCheckFullyPopulated() ? new HashSet<String>() : null);

        for (int index = 1; index <= columnCount; index++) {
            String column = JdbcUtils.lookupColumnName(rsmd, index);
            String field = lowerCaseName(column.replaceAll(" ", ""));
            PropertyDescriptor pd = this.mappedFields.get(field);
            if (pd != null) {
                try {
                    Object value = getColumnValue(rs, index, pd);
                    if (rowNumber == 0 && logger.isDebugEnabled()) {
                        logger.debug("Mapping column '" + column + "' to property '" + pd
                                .getName() + "' of type '" + ClassUtils.getQualifiedName(pd.getPropertyType()) + "'");
                    }
                    try {
                        Class<?> propertyType = pd.getPropertyType();
                        Field f = FieldCache.getField(this.mappedClass, pd.getName());
                        if (null != f) {
                            f.setAccessible(true);
                            JsonHandler toJson = f.getAnnotation(JsonHandler.class);
                            if (toJson != null && null != value) { // 说明是Json字符串 - 需要转成对象
                                if (propertyType.isArray()) {// 数组
                                    List<Object> list = JsonUtil.readValue(value.toString(),
                                            new TypeReference<List<Object>>() {});
                                    if (null != list) {
                                        value = list.stream().map(t -> JsonUtil.convertValue(t,
                                                propertyType.getComponentType())).toArray();
                                    }
                                } else if (List.class.isAssignableFrom(propertyType)) {// 集合
                                    List<Object> list = JsonUtil.readValue(value.toString(),
                                            new TypeReference<List<Object>>() {});
                                    // 获取泛型
                                    Class<?> argument =
                                            (Class<?>) ((ParameterizedType) f.getGenericType()).getActualTypeArguments()[0];
                                    if (null != list) {
                                        value = list.stream().map(t -> JsonUtil.convertValue(t, argument)).collect(Collectors.toList());
                                    }
                                } else {// 单个非java的对象
                                    value = JsonUtil.readValue(value.toString(), propertyType);
                                }
                            }
                        }
                        bw.setPropertyValue(pd.getName(), value);
                    } catch (TypeMismatchException ex) {
                        if (value == null && this.primitivesDefaultedForNullValue) {
                            if (logger.isDebugEnabled()) {
                                logger.debug(
                                        "Intercepted TypeMismatchException for row " + rowNumber + " and column '" + column + "' with null value when setting property '" + pd
                                                .getName() + "' of type '" + ClassUtils.getQualifiedName(
                                                pd.getPropertyType()) + "' on object: " + mappedObject, ex);
                            }
                        } else {
                            throw ex;
                        }
                    }
                    if (populatedProperties != null) {
                        populatedProperties.add(pd.getName());
                    }
                } catch (NotWritablePropertyException ex) {
                    throw new DataRetrievalFailureException(
                            "Unable to map column '" + column + "' to property '" + pd.getName() + "'", ex);
                }
            } else {
                // No PropertyDescriptor found
                if (rowNumber == 0 && logger.isDebugEnabled()) {
                    logger.debug("No property found for column '" + column + "' mapped to field '" + field + "'");
                }
            }
        }

        if (populatedProperties != null && !populatedProperties.equals(this.mappedProperties)) {
            throw new InvalidDataAccessApiUsageException(
                    "Given ResultSet does not contain all fields " + "necessary to populate object of class [" + this.mappedClass
                            .getName() + "]: " + this.mappedProperties);
        }

        return mappedObject;
    }

    /**
     * Initialize the given BeanWrapper to be used for row mapping.
     * To be called for each row.
     * <p>The default implementation applies the configured {@link ConversionService},
     * if any. Can be overridden in subclasses.
     *
     * @param bw the BeanWrapper to initialize
     * @see #getConversionService()
     * @see BeanWrapper#setConversionService
     */
    protected void initBeanWrapper(BeanWrapper bw) {
        ConversionService cs = getConversionService();
        if (cs != null) {
            bw.setConversionService(cs);
        }
    }

    /**
     * Retrieve a JDBC object value for the specified column.
     * <p>The default implementation calls
     * {@link JdbcUtils#getResultSetValue(java.sql.ResultSet, int, Class)}.
     * Subclasses may override this to check specific value types upfront,
     * or to post-process values return from {@code getResultSetValue}.
     *
     * @param rs    is the ResultSet holding the data
     * @param index is the column index
     * @param pd    the bean property that each result object is expected to match
     * @return the Object value
     * @throws SQLException in case of extraction failure
     * @see org.springframework.jdbc.support.JdbcUtils#getResultSetValue(java.sql.ResultSet, int, Class)
     */
    protected Object getColumnValue(ResultSet rs, int index, PropertyDescriptor pd) throws SQLException {
        return JdbcUtils.getResultSetValue(rs, index, pd.getPropertyType());
    }

}
